Warm-up

Points, Lines and PlanesSection 1.2SOL:

PointsAn undefined term in geometry.They have no sizeHow do you represent a point?

By using a dotHow do you label a Point?

With a capital letterNever use the same letter on two

different points.What are some examples of points?

Stars, Corner of the room

A

B

BXC

LinesUndefined term in geometry.They are made up of points and have no

thickness or width.They Extend indefinitely

There are 2 Ways to label lines:1. Using small script letter – line t2. Using any two points on the line –

Never name using three letters -

t XY

Z

zyzxyxyzxzxy ,,,,,

xyzX

Examples of lines:Phone lines strung between poles,

spider webs, sun beams.Collinear Points:

Points that lie on the same line.

Non-collinear Points:Points that do not fall on the same line.

A

B

BA

PlanesUndefined term in geometryAre thought of as flat surfaces that extend

indefinitely in all directions and have no thickness.

There are two ways to label planes:1. Using a capital script letter – S2. Using any three non-collinear points –

XYZ, XZY, YXZ, YZX, ZXY, ZYX

S

X

Z

Y

Coplanar:Points that lie on the same

plane.

Non-coplanar: Points that do not lie on the

same plane.

Example: Use the figure to name each of the following.

1. Give two other names for .2. Give two other names for Plane R.3. Name 3 collinear points.4. Name 4 points that are coplanar.5. Name a point that is not coplanar with points

Q,S,and T.

V

R

Q

SP

Tm

n

PQ

Example: Draw and label a figure for each relationship.

RA

P

E

B

D

C

Space

Is a boundless three dimensional set of all points. Space can contain lines and planes.

1. How many Planes are there?2. Name three points that are

collinear.3. Are points A, B, C, & D coplanar?

Explain.4. At what point do and

intersect?

AB CD

1. How any planes are there?2. Name three collinear points.3. Are points G, A, B, & F coplanar?

Explain4. At what point do and

intersect?

EF AB

Activity1. Each student gets two cards2. Label one Q and one R.3. Hold the two card together and place

a slit halfway through both cards.4. Hold cards so that the slits matchup

and slide them together. (Tape cards together)

5. Where the cards meet models a line. Draw the line and label two points C and D on the line.

Activity Cont.

1. Draw point F on your model so that it lies in Q but not R. Can F lie on line DC?

2. Draw point G so that is lies in R but not Q. Can G lie on line DC?

3. If point H lies in both Q and R where would it lie? Draw it on your model.

4. Draw a sketch of your model on your paper. Label each thing appropriately.